High-voltage analog systems that have a feedback loop may use a compensation network. For example, the compensation may be obtained with an RC network connected across terminals of a voltage amplifier within the system.
An output swing of this stage may be equal to a supply voltage, so that a capacitor of the RC network may have to sustain this difference of potential applied across it.
However, a capacitance that is able to withstand high voltages in monolithic circuits may not be available. If these capacitances are available, they may prove burdensome in terms of an area of silicon occupied on the monolithic circuit.
Purely by way of example, voltage capabilities of 1.8 V, 5 V, 20 V, and 40 V may correspond to values of capacitance/area ratio (expressed in nF/mm2) of 8.45, 2.37, 0.741, and 0.139, respectively.
A pole-zero compensation may be achieved via an RC network set at an output of an input stage. This may, however, lead to a lower control of the gain of the voltage amplifier as a function of the conditions of load, which may lead to instability in some areas of operation. To avoid this, it may be possible to contemplate reducing the frequency of the compensation pole, with consequent increase in the value of the capacitance and hence in the area of silicon.